1. Field of the Invention
This invention relates to a liquid propellant injector for use with a rocket thruster, more particularly to an improved injector defining combustion chamber therein.
2. Prior Art
Various injectors have been utilized with rocket propulsion systems in the past. U.S. Pat. No. 5,765,361 shows an injector which provides the oxidizer as well as the fuel axially in the direction of a nozzle. The igniter engine shown in FIG. 1A initially provides oxidizer to start the combustion process. Axially directed propellants typically take a relatively long combustion chamber to ensure that propellants mix and completely combust prior to exiting the nozzle.
U.S. Pat. No. 4,586,226 operates somewhat similarly to the '361 patent. Fuel is provided axially in the direction of the nozzle in the illustrated injector from a face plate at the chamber head end. In this design, the oxidizer is directed at an angle to intersect the flow path of the fuel and then proceed axially towards the nozzle (not shown).
In designs which axially direct propellants, the combustion chamber walls are typically cooled by film cooling or some other means, to prevent material degradation. These cooling concerns are believed to create a loss in performance. Additionally, traditional injectors often require a long time to fabricate and are usually costly to produce.
In order to overcome potential disadvantages of a long combustion chamber, numerous efforts have been undertaken to provide tangentially directed propellants. In U.S. Pat. No. 3,937,012, the oxidizer is initially supplied axially and inwardly to the fuel which then impinges upon a impeller to provide a tangential aspect to the flow of propellants. The oxidizer provides a cooling veil over the top surface of the impeller. (Column 4, lines 40-45.) The impeller design is believed to add to the complexity of the injector and possibly provide a point of failure and increased costs.
U.S. Pat. No. 3,640,072 shows a simpler combustion chamber for use with the rocket that directs propellants tangentially into the combustion chamber to the combustion sidewalls rather than actually at the head end of the chamber. The liquid propellants impinge along the chamber walls which is believed to impose the greatest thermal loads at the point of impingement along the walls. These thermal stresses are believed to be high enough to drastically reduce the life of the components.
While there have been a number of improvements in basic combustion chamber design, a need still exists to provide a low cost injector which is robust, requires little maintenance and may be reused. A need also exists to provide an engine combustion chamber having reduced complexity, cost of fabrication and overall weight.